rcpigz: R u the Hulk? =)
I would say that you might be stronger than you thought! =)
Really, most RC cars are built with soft parts for a reason. Maybe the diff housing doesnt need to be screwed THAT tight, I usually find that i can stop tightening as soon as the screw bottoms out. I've managed to strip the screw holes in my TC3 as well, the easy fix is to drop some CA in the hole then re thread it. If you dont tighten it too hard, the worst that could happen is more frequent rebuilds but most parts fit really nicely together so the dirt/dust prevention is pretty good.